Question by Jessica B.
The leaves of my jacaranda tree, which is only a year old, are turning brown from the tips of the leaves and the whole tree has a yellow look to it. I do not believe it is heat scorch because the days have been cool. I have sprayed the tree with pesticide because ants were all over it. Any ideas and tips would be much appreciated.
Sarah's answer
Hi Jessica,
It is most likely you had a sap sucking insect pest that was reducing the vigour of your young tree. This is a high possibility because of the presence of ants as they will farm the sap suckers for their honeydew. So have a close look, beyond the ants, and see if you can see aphids or scale. Having said that, the spray you used may have taken care of them, so keep vigilant in case they return. If you sprayed in the heat of the day, this could have caused a scorch effect. Ideally it is best to spray insecticides in the early morning or late evening with the added advantage of being less likely to harm bees and other pollinators.
Other possible reasons for yellowing leaves include:
- It could be watering issues. It is best to water well, so it soaks deep into the ground and then leave it until the soil surface is dry before watering again. But don’t leave it too long between watering. Every other week should be good enough.
- Alongside watering, it is important that the soil drains well since if the ground is too soggy this can cause root rot, which can cause yellowing leaves and other symptoms and increases the risk of other diseases to enter the plant.
- Over-fertilising can also cause problems, so make sure you use a fertiliser at a recommended rate that is suitable for your tree, ideally low in nitrogen to help promote flowering.
- It could also be the cold weather, young jacarandas don’t like cold weather and should be protected for the first couple of years, especially from frost. Once they get older, they adapt to their conditions and it is no longer a problem.
Finally, this could be part of the deciduous process; however, they only lose their leaves for a short time in late winter to spring so it is too soon for this, but the leaves will fall soon enough.
I hope this helps and your plant returns to full health and provides beautiful blooms for seasons to come.
Cheers Sarah
